1. Field of the Invention
The present invention relates to an upright vacuum cleaner.
2. Description of the Prior Art
Generally, an upright vacuum cleaner cleans the floor surface by sucking foreign objects. As illustrated in FIGS. 1, 2, 3 and 4, a prior art vacuum cleaner disclosed in U.S. Pat. No. 4,217,674 includes a suction apparatus 10 constructed to clean the floor surface by rotating an agitator 11 connected to a motor shaft A via a rubber belt B and implanted with brushes. The apparatus 10 is supported by left and right auxiliary front wheels 12. A body 20 is rotatably mounted to the suction apparatus 10 and is supported via rear wheels 21 disposed at left and right sides thereof. Dust is sucked through the suction apparatus 10 according to suction force. A handle member 30 is arranged at an upper portion of the body 20 for being pushed and pulled by a user, and a suction hose 40 mounted to the body 20 and the apparatus 10 for conducting the sucked-in dust.
When electric power is applied to activate driving means (not shown) in the body 20, and the handle member 30 is pushed forward or pulled backward at a predetermined angle, the wheels 21 at the body 20 are rotated and when, as illustrated in FIG. 4, when an angle formed by the body 20 and the floor surface is changed from 90 degrees to 38.7 degrees, (i.e., a normal use position) a gap between a suction opening of the suction apparatus 10 and the floor surface is also changed from (F) to (E) in FIG. 4. That occurs because the rear wheel 21 moves forwardly to a position beneath the shaft A, causing the shaft A, and thus the suction apparatus 10, to raise up and produce a corresponding lowering of the front portion of the apparatus 10 as the apparatus 10 rotates counterclockwise about the axis of front wheels 12. In other words, when the cleaning is performed at this time, cleaning efficiency is improved because the agitator 11 is rotated at the closest distance from the floor surface.
Thereafter, when the body 20 is again rotated to a position of 90 degrees, the gap (F) is recreated.